Do the Masaya 'combo' tour which takes in Masaya Volcano, Masaya Artisans Market, Laguna de Apoyo and the pottery making town of San Juan de Oriente.
Contact Maria Jose firstname.lastname@example.org
She's from Masaya and speaks English.
Las Isletas - you can go down to the lake in a $2 taxi ride from Granada, get on one of the boats for a tour - you don't need a guide.
Another option is to see them on a kayak tour, lots of people in Granada do this tour.
Mombacho Volcano has a beautiful cloud forest at the top, well worth seeing for the wildlife and flower and fauna but take a sweater.
When you first get into Granada there are horses and carriages in the central square which will take you on a quick tour round the town for about $5 plus tips.
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